Overhead Feeder Switching
Switching 11, 22 and 33 kV overhead feeders under load, for maintenance, load transfer and fault isolation.
Switchgear
Load break switches for MV networks.
Premium, state of the art outdoor and indoor load break switches for 11 to 33 kV networks, including 60 Hz 13.8 and 34.5 kV systems, rated 12 to 38.5 kV and 400 to 1,250 A.
Pole mounted switches quench the arc in oil or vacuum, and indoor switches combine with high voltage fuses for transformer protection, including 60 Hz air insulated panel switches with no oil or gas. Most switches are also disconnectors, so one device switches load current and provides safe isolation.
- Voltage class
- 12 to 38.5 kV
- Rated current
- 400 to 1,250 A
- Arc quenching
- Oil, vacuum or air
- Installation
- Outdoor and indoor
The range
Our load break switches are switch disconnectors to IEC 62271-103: they make and break load current and, when open, provide the isolating distance of a disconnector. Switch fuse combinations are to IEC 62271-105.
Outdoor Load Break Switches, Oil Arc Quenching
Pole and structure mounted three pole switches rated 12, 24, 36 and 38.5 kV and 400 or 630 A, with the arc quenched in oil filled chambers. Available in two designs.
Outdoor Load Break Switches, Vacuum
Pole and structure mounted three pole switches rated 12, 24, 36 and 38.5 kV and 400, 630 or 1,250 A, with vacuum interrupters and no oil.
Indoor Switch Disconnectors, 12 to 38.5 kV
Multipurpose switch disconnectors rated 400, 630 or 1,250 A for indoor switchboards and substations, also supplied as switch fuse combinations.
Indoor Switch Disconnectors, 12 and 24 kV
Switch disconnectors rated 400, 630 or 1,250 A, with several switch fuse arrangements for transformer and feeder circuits.
Transformer Switch Disconnectors, 24 kV
Switch disconnectors rated up to 400 A for transformer feeders, combined with high voltage fuses.
Indoor Air Insulated Load Break Switches, 24 kV, 60 Hz
Premium, state of the art panel mounted three pole switches rated 24 kV and 630 A at 60 Hz, for 60 Hz networks such as those in the North Pacific, and built to the highest IEC electrical endurance class, E3. An air puffer blows out the arc as the contacts open, with no oil or gas. Fuse versions take current limiting fuses up to 100 A, where many comparable switches stop at 63 A, carry a 1,250 A transfer current, and trip all three phases if one fuse blows, so a transformer never runs on two phases. Operated from the panel door by cable or by motor, with a shunt trip for protection relays.
High Voltage HRC Fuses
Fuse links rated 7.2 to 40.5 kV and up to 160 A for indoor and outdoor use, with striker pin, optional thermal protection, and versions suitable for SF6 switchgear.
Manual and Motor Operation
Single, double and triple hand actuators, or a motor drive for remote switching and network automation.
Specifications
Typical ratings for the standard range. Final values are confirmed for each project.
Customised designs available. If your project needs ratings, features, design requirements or arrangements outside the standard range below, we design and manufacture to your requirements and application.
Technical dataLoad break switches
| Parameter | Standard | Optional or on request |
|---|---|---|
| Switch types | Outdoor three pole load break switches; indoor switch disconnectors; indoor air insulated load break switches; switch fuse combinations | Customer specific multipole switches |
| Arc quenching, outdoor switches | Oil or vacuum | |
| Rated voltage | IEC: 12, 24, 36 and 38.5 kV, 50 Hz IEEE/ANSI: 15.5, 27 and 38 kV, 60 Hz | |
| Rated current | ||
| Outdoor, oil | 400 A, 630 A | |
| Outdoor, vacuum | 400 A, 630 A, 1,250 A | |
| Indoor, 12 to 38.5 kV | 400 A, 630 A, 1,250 A | |
| Indoor, 12 and 24 kV | 400 A, 630 A, 1,250 A | |
| Transformer switch disconnector, 24 kV | Up to 400 A | |
| Indoor air insulated, 24 kV | 630 A | Fuse versions with fuses up to 100 A |
| Indoor air insulated load break switches, 24 kV | ||
| Rated frequency | 60 Hz | |
| Switch class | E3 electrical, M1 mechanical (IEC 62271-103) | |
| Short time withstand current | 20 kA for 1 second | |
| Making current | 52 kA peak | 104 kA peak with fuses |
| Breaking current with fuses | 40 kA | |
| Transfer current | 1,250 A (fuse versions) | |
| Lightning impulse withstand | 125 kV to earth; 145 kV across the open gap | |
| Power frequency withstand | 50 kV to earth; 60 kV across the open gap | |
| Switching duty | 100 operations at 630 A; 20 loop switching operations; cable and line charging; 1,000 no load operations | |
| Operation | Manual from the panel door by flexible cable | Motor operation, 110 V DC or 110 and 220 V AC; shunt trip; auxiliary contacts |
| Fuse protection | Trips all three phases if one fuse blows; blown fuse indication contact | |
| Ambient conditions | Up to +40°C; altitude up to 1,000 m | |
| High voltage HRC fuses | ||
| Rated voltage | 7.2, 12, 24, 36 and 40.5 kV | |
| Rated current | Up to 160 A | |
| Features | Striker pin; indoor and outdoor versions | Thermal protection; versions for SF6 switchgear |
| Operation | Hand actuators, single, double or triple | Motor drive |
| Standards | IEC 62271-103; IEC 62271-105; fuses to IEC 60282-1 | |
Design and performance
Premium, state of the art switches engineered for reliable load switching and safe isolation, outdoors and indoors.
Switch and Disconnector in One
Each switch makes and breaks load current and, when open, provides the isolating distance of a disconnector, so a separate isolator is not needed.
Oil or Vacuum Arc Quenching
Outdoor switches are available with oil filled arc quenching chambers or with vacuum interrupters and no oil, so the choice can follow network practice and maintenance preference.
Fuse Protection for Transformers
Switch fuse combinations protect distribution transformers with high voltage HRC fuses, and striker pins signal a blown fuse.
Ready for Automation
Outdoor switches take a motor drive for remote switching from a control room or automation scheme, alongside manual hand actuators.
Customer Specific Designs
Multipole and customer specific switch arrangements are available on request.
Highest Endurance Indoor Switching
The indoor air insulated switches meet the highest IEC electrical endurance class, E3, with a spring operating mechanism built for long service life. Fuse versions protect transformers up to about 2.6 MVA with fuses up to 100 A, and a mechanical fuse trip opens all three phases when a single fuse blows.
Applications
Delstar supplies load break switches for:
Network Automation
Motorised switches for remote switching and feeder automation schemes.
Pole Mounted Transformers
Switching and isolating transformers on overhead networks.
Indoor Substations and Switchrooms
Switch disconnectors and switch fuse combinations for MV switchboards in substations, kiosks and plant rooms.
Industrial and Mining Networks
MV distribution on mine sites, plants and private networks.
Renewable Generation Connections
Switching points where solar farms and other generation connect to the network.
Sourcing and quality assurance
Our load break switches are premium products from established manufacturers. The outdoor and European indoor ranges are made by a switchgear maker with over a century of experience, and the 60 Hz air insulated switches by an established Asian manufacturer of medium and high voltage switchgear whose group builds equipment to nuclear power plant quality standards. All are type tested to IEC 62271-103, with switch fuse combinations to IEC 62271-105. Delstar delivers to site across New Zealand, Australia and the Pacific.
Lifecycle support
- Specification and configuration: we help select the arc quenching type, rating, fuses, mounting and drive for each site.
- Spares and asset management: fuse links, drive parts and contacts can be held locally.
Talk to our team
Specify your load break switch requirement.
Send us your network voltage, rated current, fault level, indoor or outdoor installation and site conditions, and we will recommend the right switch and confirm availability, lead time and local support.